The present invention relates to improvements in apparatus for loading and unloading containers for photosensitive material, especially for removing exposed sheet of X-ray film from and/or introducing unexposed sheets of X-ray film into cassettes of the type wherein two or more sections of the cassette are coupled with but movable relative to each other and can be locked to each other in closed position of the cassette.
It is known to load or unload cassettes for X-ray film in a lighttight housing wherein an exposed sheet of X-ray film is transferred into a tray and the cassette thereupon receives a sheet of unexposed film. It is also known to equip such housings with mechanisms for unlocking a freshly admitted cassette so as to allow for removal of exposed film and subsequent introduction of an unexposed sheet.
German Pat. No. 1,497,446 discloses an apparatus wherein the cassette is placed onto a pivotable horizontal table which is installed in a lighttight housing. The table is pivoted in a first direction and cooperates with a first device which unlocks a cassette on the table so that the cassette is allowed to assume a partly open position whereby the exposed sheet is supposed to leave the cassette under the action of gravity. The table is thereupon pivoted back to and beyond the horizontal position, and the cassette thereon is opened by a second device so as to allow for introduction of an unexposed sheet. Removal of the freshly loaded and locked cassette takes place subsequent to pivoting of the table back to its horizontal position.
Such apparatus are quite complex, bulky and expensive. Furthermore, the interval which elapses between introduction of a cassette containing exposed film and the withdrawal of such cassette (with a sheet of unexposed film therein) is long. Opening of the housing for insertion or withdrawal of cassettes also takes up a substantial amount of time. Such opening necessitates unlocking of a lid and movement of the lid to an open position. The same procedure is repeated in reverse order upon insertion of the next cassette. The opening is rather narrow and does not allow for predictable insertion of successive cassettes with little loss in time.